Force calculator

Force equals mass times acceleration, solved for any one of the three.

Formula Science & engineering

Force

In kilonewtons: 0.1 kN
In kilogram-force: ≈ 10.1972 kgf
In pound-force: ≈ 22.4809 lbf

How it works

Newton’s second law says the net force on an object equals its mass times its acceleration. One newton accelerates one kilogram by one metre per second squared.

A negative acceleration means slowing down, which needs a force in the opposite direction. Kilogram-force uses standard gravity, 9.80665 m/s², and one pound-force is exactly 4.4482216152605 N.

Formula

F = m × a
m = F ÷ a
a = F ÷ m
1 kgf = 9.80665 N

Worked example

Pushing a 20 kg trolley to accelerate at 5 m/s² takes F = 20 × 5 = 100 N, about 10.2 kgf or 22.48 lbf.

Questions people ask

What is a newton?

The SI unit of force: the force that gives 1 kg an acceleration of 1 m/s². An apple weighs roughly 1 N.

How do I find weight from mass?

Use a = 9.80665 m/s², standard gravity. A 70 kg person weighs about 686.5 N on Earth.

Is this the net force?

Yes. F is the total of all forces acting; friction and air resistance must be subtracted from the push to get it.